my Quantum fireball is only 3 Gb so I need something else to backup the replacement IBM I will eventually receive. But what is the best drive, are the later IBMs as prone to failure or is Western Digital the thing to try ?

I ran Drive Fitness Test and got 0x70 and 0x77 codes which indicates a defective device and gave me an RMA code.

Also managed to backup all data except some C drive onto the Quantum. Luckily I keep most of my stuff off C drive having experienced jumper virus a couple of years ago.